A raised fist goes back much further in history, at least to the French revolution, not sure about before that. Its always been a symbol of solidarity and anti-fascism. Eyes have been used as a symbol, as in bearing witness to whats going on. Keith Haring created some incredible iconography like the 3 eyed monster, barking dog, etc. Colors by themselves have been used to mark activism. Then you have more generic symbols that have been used, like a bullhorn, scales of justice, pitchforks, etc.

the image on the adobe link isn't displaying for me for some reason, but i think multiple raised fists might be cool to use, like this one:

https://www.flaticon.com/free-icon/black-lives-matter_4797126

or maybe something with signs: https://www.flaticon.com/free-icon/social-justice_10523661

https://www.flaticon.com/free-icon/green_2641213

basically i'm voting for colourful icons as an aesthetic choice, & icons with multiple people to keep a focus on collectivism :)

Yeah I think that would work. I also would say a stylized megaphone could work or maybe a symbol that includes multiple people aimilar to this one.